Thanks. That works, but it leaks the syntax class abstraction a little bit.
I figured out I can also get the behavior I want with ~peek On Fri, Jun 13, 2014 at 3:27 PM, J. Ian Johnson <i...@ccs.neu.edu> wrote: > I use ~and patterns to first match structure and then match syntax classes to > do what you're doing. > -Ian > ----- Original Message ----- > From: Stephen Chang <stch...@ccs.neu.edu> > To: Racket Users <users@racket-lang.org> > Sent: Fri, 13 Jun 2014 15:03:44 -0400 (EDT) > Subject: [racket] pass pattern vars as syntax-class args before they appear > in syntax-parse pattern > > I want to do something like this: > > #lang racket > (require syntax/parse) > > (define-syntax-class (myclass . args) > (pattern x:id)) > > (syntax-parse #'(a (b c)) > [((~var x (myclass #'(y ...))) ... > (y z) ...) > #'(x ...)]) > > But this doesnt work because I'm trying to pass y before it is bound. > Is there an elegant way to do this, while still preserving my > syntax-class abstraction? If I leave x undeclared initially and then > use #:declare, then x ... will match everything, which I dont want. > > I'm almost certainly missing something obvious but I can't figure it out. > ____________________ > Racket Users list: > http://lists.racket-lang.org/users > ____________________ Racket Users list: http://lists.racket-lang.org/users
